using PkmnLib.Dynamic.Models;
using PkmnLib.Plugin.Gen7.Scripts.Moves;
using PkmnLib.Static;

namespace PkmnLib.Plugin.Gen7.Tests.Scripts.Moves;

/// <summary>
/// Tests for the <see cref="GyroBall"/> move script.
/// Gen VII Bulbapedia behavior: "Gyro Ball inflicts more damage the slower the user is compared to the
/// target", with base power = min(150, 25 × target Speed / user Speed + 1).
/// </summary>
public class GyroBallTests
{
    private static (GyroBall script, IExecutingMove move, IPokemon target) CreateTestSetup(uint userSpeed,
        uint targetSpeed)
    {
        var script = new GyroBall();
        var move = Substitute.For<IExecutingMove>();

        var user = Substitute.For<IPokemon>();
        user.BoostedStats.Returns(new StatisticSet<uint>(100, 100, 100, 100, 100, userSpeed));
        move.User.Returns(user);

        var target = Substitute.For<IPokemon>();
        target.BoostedStats.Returns(new StatisticSet<uint>(100, 100, 100, 100, 100, targetSpeed));

        return (script, move, target);
    }

    /// <summary>
    /// Bulbapedia: "BasePower = min(150, 25 × CurrentSpeed(target) / CurrentSpeed(user) + 1)". Various
    /// speed combinations, including the integer truncation of the division.
    /// </summary>
    [Test, Arguments(100u, 100u, (ushort)26), Arguments(100u, 50u, (ushort)13), Arguments(100u, 1u, (ushort)1),
     Arguments(50u, 200u, (ushort)101)]
    // 25 * 100 / 100 + 1
    // 25 * 50 / 100 = 12 (truncated) + 1
    // 25 * 1 / 100 = 0 (truncated) + 1
    // 25 * 200 / 50 + 1
    public async Task ChangeBasePower_SpeedComparison_FollowsFormula(uint userSpeed, uint targetSpeed,
        ushort expectedPower)
    {
        // Arrange
        var (script, move, target) = CreateTestSetup(userSpeed, targetSpeed);
        ushort basePower = 5;

        // Act
        script.ChangeBasePower(move, target, 0, ref basePower);

        // Assert
        await Assert.That(basePower).IsEqualTo(expectedPower);
    }

    /// <summary>
    /// Bulbapedia: "The move reaches its maximum base power of 150" — a formula result just above the cap
    /// is clamped to 150.
    /// </summary>
    [Test]
    public async Task ChangeBasePower_FormulaExceedsCap_BasePowerCappedAt150()
    {
        // Arrange - 25 * 60 / 10 + 1 = 151
        var (script, move, target) = CreateTestSetup(10, 60);
        ushort basePower = 5;

        // Act
        script.ChangeBasePower(move, target, 0, ref basePower);

        // Assert
        await Assert.That(basePower).IsEqualTo((ushort)150);
    }

    /// <summary>
    /// Bulbapedia: the base power is capped at 150 for any speed ratio. The implementation truncates the
    /// formula result to a byte before applying the cap, so results above 255 wrap around and produce a
    /// wrong power (25 × 100 / 4 + 1 = 626 wraps to 114).
    /// </summary>
    [Test]
    public async Task ChangeBasePower_FormulaFarExceedsByteRange_BasePowerCappedAt150()
    {
        // Arrange - 25 * 100 / 4 + 1 = 626
        var (script, move, target) = CreateTestSetup(4, 100);
        ushort basePower = 5;

        // Act
        script.ChangeBasePower(move, target, 0, ref basePower);

        // Assert
        await Assert.That(basePower).IsEqualTo((ushort)150);
    }

    /// <summary>
    /// Bulbapedia (Generation VI onwards): "If the user of Gyro Ball has a Speed stat that rounds down to
    /// 0, the move's power is set to 1."
    /// </summary>
    [Test]
    public async Task ChangeBasePower_UserSpeedIsZero_BasePowerIsOne()
    {
        // Arrange
        var (script, move, target) = CreateTestSetup(0, 100);
        ushort basePower = 5;

        // Act
        script.ChangeBasePower(move, target, 0, ref basePower);

        // Assert
        await Assert.That(basePower).IsEqualTo((ushort)1);
    }
}